A storage-type water heater typically comprises a permanently enclosed water tank, a cylindrical shell coaxial with and radially spaced apart from the water tank to form an annular space between the outer wall of the water tank and the inner wall of the shell, and insulating material in at least a portion of the annular space for providing thermal insulation to the water tank. The water tank has various appurtenances such as inlet, outlet, and drain fittings. Additionally, the water heater is provided with a water heating and temperature control system. The water heating and temperature control system includes a heating element to heat the water.
Conventional water heating and temperature control systems typically further include a mechanical thermostat. In electric water heaters, the mechanical thermostat closes a switch to allow electrical power through an electrical resistance heating element when water in the tank is sensed to be below a selected set-point temperature, and opens the switch to stop electrical power from passing through the electrical resistance heating element when the water in the tank is at or above the set point temperature.
Conventional water heaters often employ a bimetallic disk and/or multiple sensors to determine the temperature in a water heater. The readings from these sensors are then averaged and that average is transmitted to the temperature control system to activate the thermostat. These systems are often not cost effective, though, due to the number of sensors required to accurately measure the temperature. It would be beneficial to provide more effective temperature sensing in the conventional water heater to provide for more efficient temperature control of the water heater.